The purpose of the present project is to develop and validate the use of ultra-small RFID chips to tag and track tissue cassettes and glass slides that are used in histopathology laboratories. The system is based on the PharmaSeq laser light-activated microtransponder, also known as p-Chip. The chip's major advantages are its small size (500 m x 500 m x 100 m), unitary design, inertness, ease of use and very low cost. The system consists of the p-Chip-tagged glass slides and tissue cassettes, a stationary reader, a portable reader for trays with slides, and associated software that allows integration with common database software. The main goals of the project are to: 1) develop semi-automated methods of attaching p-Chips to slides and cassettes, 2) build advanced prototypes of the ID reader (wand) and improve key features, such as the form factors for reading each type of container, 3) improve the design of the p-Chip to increase the read range and refine methods of their post-fabrication processing, and 4) conduct extensive pilot test studies with outside collaborators to validate the system. The ID readers will have a modified optical system and will feature wireless communication between the reader and a workstation or central computer. The adoption of the system will improve reliability for tagging and tracking tissue samples.